Idle Problem

plese help, im having problems w my new deuce. sometimes it idles great then after a while it starts dropping a cylinder. just for a second kinda like "puduhhhhh". then normal again, then the drop. untill the drops get worse and worse and it doesnt want to idle at all. then it just dies. i then have to crank and crank and crank and mash the pedal. all of a suddden "vrooooom". and its idleing normal again untill the cycle starts over. this could be days or in a span of 30 minutes. is it possible i have an air leak in the fuel system. is there supposed to be air in the RETURN side? plese help obewan , youre my only hope!

On mine, I do not smell raw diesel, or see fuel dripping, so you may want to look for indication of a leak. If you smell diesel, or see fuel dripping, then a leak could be the problem. All I smell around the engine is a faint coolant smell, and maybe some oil.

Also, I think if there was air in the return, the fuel tank would have a lot of foam after driving it around.

My truck will start into a lope, or rolling idle for a couple of revs, then stop. I've been told that's normal, but stalling would not be.

There's a bleed on top of the secondary filter housing that you can crack open with the fuel pump on. You should get pure fuel, not foam or air from this port. Any sign of air and that's the problem. Try it just as it starts dropping cylinders too.

So it runs good otherwise, when driving? It wasn't idleing for too long?

most times it runs great. drive it to work 50 miles each way. i noticed though that when the problem happens it lacks power. no visible fuel leak, although when i first got it fuel was leaking from the cold start fuel pump. i ran the cold start pump while cranking a few times and it stopped. hasnt leaked since. fuel density compensator has been bypassed and tubing was looped around from fitting to fitting? is that right?

Yeah, mine is looped that way too.

Just thinking out loud. A diesel will run if it gets fuel. Give it more fuel, and it will make more power. If it gets fuel and not enough air, it will smoke. That's why the turbo was added, to get more air, so that it would smoke less. So, if you don't see smoke when this happens, and it's losing power, it must not be getting the fuel.

Not knowing the internal issues of those injector pumps, I can't say what, other than air, would do this. I ran my tank down on a long highway trip once. After 1/8th a tank, I noticed I was losing power. Maybe there's something in the tank that gets in the way of the intake or something? A beer can?<img src="emoticons/icon_smile_lol.gif" alt="LOL">

I can see it now..... A drunk Deuce<img src="emoticons/icon_smile_rotfl.gif" alt="ROTFL">

got a chance to mess w/ the truck the other day. followed your advice and turned on the tankl pump and bled the 2nd and final fuel filters w/ the little bleeder screw on top. wow, there was a lot of air in there. but how did it get there? after i did that it ran great. fires right up every time. idles great. ive been checking for air at the bleeder , but as of yet it has not returned. i know that the guy i bought th truck from replaced the fuel filters before i got the truck. posssibly he didnt bleed the air after changing them? maybe its a small leak and it takes a while to build up all that air? is it possible that the air was allways in there and only gets sent to the injection pump intermittantly. like when i would drive off road and shake the truck all up?

Could be it was there from the filter change. Once, I opened the drain on the primary filter with the pump off and heard a gurgling. It was sucking air into the housing, so there must be slight vacuum on the system when off, just to hold the fuel in the lines. If you had an air leak, I would think it would build up over time due to that.